This invention is concerned with a blowhead arrangement for a glassware container manufacturing machine comprising a blowhead and a support therefor, the support defining a passage through which a supply of air under pressure supplied to the support can be transmitted to a blowing passage in the blowhead so that, when the blowhead is positioned with its blowing passage in communication with the opening of a glass parison in a mould cavity, air from the blowing passage blows the parison to the shape of the mould cavity.
In the manufacture of glassware containers, parisons are formed either by a pressing or a blowing operation and are transferred to a mould for final blowing to the shape of a mould cavity. The parison is positioned in the mould and a blowhead is moved into position on the parison so that air under pressure can be blown from the blowhead into the parison to cause it to expand to the shape of the mould cavity. In some types of blowhead, a passage through the blowhead is aligned with the opening in the top of the parison and air is merely blown through the passage and into the opening of the parison so that a pressure above atmospheric pressure is achieved in the parison. With this type of blowhead, the air entering the parison causes very little cooling effect to the parison and this cooling does not affect the portion of the parison around the opening into the parison (which portion is hereinafter called the "finish" of the parison) by which the parison is supported in the mould. In other types of blowhead, a tube extends from the blowhead into the parison and air is blown through the tube into the parison and escapes from the parison by passing back into the blowhead through a passage which is coaxial with and surrounds the tube. The air passing back into the blowhead passes to a throttled exhaust which is set to achieve the desired blowing pressure in the parison. With this type of blowhead, there is a more marked cooling effect on the parison caused by the air entering it from the blowhead because there is a greater flow of air through the parison. However, this cooling hardly affects the finish of the parison. It is, however, desirable that the finish of the parison should be cooled to prevent it from distorting and causing the parison to collapse within the mould and also so that takeout means which removes the container from the mould can safely grip the finish.
It is an object of the present invention to provide a blowhead arrangement for a glassware container manufacturing machine by which the finish of a parison being blown by the blowhead is subjected to increased cooling.